Television system



Aug. (5, 1935.

A. M L. NICOLS ON TELEVISION SYSTEM Filed Jan. 27, 1932.

ATTORNEY Patented Aug. 6, 1935 UNITED STATES TELEVISION SYSTEM Alexander McLean Nicolson, New York, N. Y., assignor to Communication Patents, Inc., New York, N. Y., a. corporation of Delaware Application January 27,

, 11 Claims.

This invention relates to the art of picture transmission wherein an object or image is explored by a unit ray of light, the light being modified by the shade intensities of the object 51 and transformed into electrical currents for transmission through space or over wires for reproduction by a similar light ray at a rate sufiicient to provide the illusion of motion.

An object of the invention is to scan or explore an objector image with a unit ray of light in a simple and efiicient manner.

Another object of the invention is to utilize substantially the entire radiation from a light source by the concentration thereof into a scanning or exploring ray.

A further object of the invention is to provide an improved optical transmission system for a television system.

A still further object of the invention is to employ an electrodynamic are as a light source, the light ray therefromhaving two coordinates, one provided by a magnetic field and. the other by a moving optical system.

It is well understood in the art of picture transmission at a speed sufficient to provide the illusion of motion, commonly known as television how to produce a ray of light and how this light maybe progressed over an area to be scanned in unit sections. Such systems have utilized spiral apertured discs, vibrating mirrors, slotted drums etc. all of which have the disadvantage of utilizing only a small proportion of the light from the light source, thereby creating a very inefficient scanning or projection system for television.

The present invention overcomes the disadvantage of light loss, except that lost by absorption in the lens or reflectors, by collecting substantially all the light energy by a concentrating lens into a unit light ray. Another advantage of the present invention is the ability to scan large areas either at the transmitter or receiver since an extremely strong pencil of light is obtained as the exploring ray; Furthermore, the apparatus required is of small dimensions in com- 45 parison with that of an apertured disc'scanning system where a disc or drum of impractical size is required for the same picture. With the arrangement of an optical projecting system in accordance with this invention. observation screens in the neighbourhood of six feet square may be employed without loss of definition due to size, at the same time requiring apparatus of practical dimensions having moving parts which rotate at comparatively low speeds.

The invention will be more fully understood 1932, Serial No. 589,206

as to its fundamental principles and its practical application by reference to the following descripe tion read in conjunction with the accompanying drawing in which:

Figures 1 and 2 are plan and elevational views 5 respectively, of one embodiment of the inven-- tion:

Figs. 3 and 4 are detailed views of the light source and lens arrangement for the system of Figs. 1 and 2: 10

Figs. 5 and 6 are partially diagrammatic and schematic drawings of another embodiment of the invention employing an electrodynamic arc as the light source.

Referring specifically to Figs. 1 and 2, a series of reflectors 5 spirally arranged upon a cylinder 6 are rotated by a motor I through a bevel gear system 8. The motor 1, by means of gear systems 9 and I0. rotates a series of annularly arranged lenses l2 on a drum I3. Positioned concentrical- 1y within the drum is a light source of any suitable type such as a crater neon lamp Hl, with'its associate reflector, the lamp being energized from an energy supply [5. Light projected from the lamp is gathered by the lenses l2 and concentrated on the mirror reflectors 5 and thereby re flected on an object to be transmitted or a receiving screen l1, depending on whether the apparatus is used as a transmitter or receiver. All the above apparatus may be mounted on a 30 base l8.

In Figs. 3 and 4, the rotating lens system is shown more in detaihthe lenses 1.! being shown mounted upon the drum l3 which is provided with an annular rack 20' adapted to engage a 35 pinion 2|. The pinion 2| is connected by a shaft 22 to bevel gears I0 which are rotated by the motor I; The energy supply I5 is supplemented by the output of a receiver l6 which has impressed thereon incoming energy from antenna I 9. When the light source I4 is used as a receiver, it is only necessary to connect the output of the picture receiver across the direct current source I5 for modulating the light from the source I4 in accordance with the incoming signal which has been modulated with currents characterized by the light and shade densities of an object scanned at the transmitter.

The operation of the above system is extremely simple. Used as a transmitter the screen H as stated above may be the object which is to be scanned the light therefrom being reflected into a photoelectric cell in the well known manner. The light source M. when transmitting. may con- V stitute any type of light source of constant in- :asmuch as five tensity such as an incandescent light, arc lamp, or the like. Upon energizing the motor 7, a light ray gathered by a lens Hi from the source I4 is projected on the lower end of the cylinder 6. The cylinder 6 is geared to the drum l3 so that the lowest reflector element appears in the ray of light. It is to be understood that these refiectors may be concave to further concentrate the beams for distant projection or may be tilted in any desired position to provide the proper di rectional eiiects. Assuming that there are 66 reflectors to provide a picture having 69 lines then the light will remain on each reflector during six degrees of its travel, during which time a beam of light will be horizontally projected across the object ll. When the lens l6 has moved the light ray to the next reflecting element on the cylinder 5, the second line will be formed immediately above the first one. Further movement of the lens and cylinder traces light lines with substantially all the light from the source 94 until the last or sixtieth line is formed when the cycle is repeated. Of course, scanning may be from top to bottom by reversing the motor.

Assuming the standard television transmission broadcast, namely 68 lines to each picture at the rate of twenty pictures per second, then the speed of the drum 5 is at the rate of twenty per second or twelve hundred per minute. However, the rate of speed of the drum i3 is much less than this inlenses are used which means that the rate of twelve hundred per minute is divided by 5 making the drum speed 2453 revolutions per minute. By further increasing the number of lenses the drum speed may be still further reduced. It is obvious, therefore. that very low rotating speeds are required which permit the useof low powered motors as a power source.

When the above system is employed as receiving equipment, a light field will be projected on the screen ll of constant intensity and varied per unit area by the fluctuation in light intensity produced by the output of the receiver 55 (Fig. 3) which varies the constant voltage supplied from the source IE. It is to be understoodthat the source l5 may be eliminated at the receiving station if the output of the receiver is sufiicient tooperate the lamp M. By synchronizing the driving elements at the transmitter and receiver in any well known manner, such as operating synchronous motors from the same frequency controlled power supply, it is only necessary to start the motor at the receiver to produce the picture in its proper position on the screen since the two rotating elements are positively connected and cannot get out of adjustment.

Referring now to Fig. 5, a motor 35 drives through a bevel gear system 3!, a cylinder 32 in which are positioned spiral concentrating lenses 34, similar to the reflectors 5 in Figs. 1 and 2. In accordance with standard television transmissions, the number of lenses may be sixty to provide a sixty line picture, and the speed of the rotation of the cylinder may be at the rate of twelve hundred per minute the diameter of the cylinder being small so that no heavy structure is necessary. Located within and parallel with the of the cylinder 32 are electrode rails 36 having a starting gap 37 and a blow out terminal 38. The electrode rails are energized from a source of voltage lil under control of rheostat fill. Located around the drum 52 so as to provide a uniform magnetic field in which the electrodes 36 are positioned, is a rectangular shaped coil represented by a single turn 43 which is supplied from a direct potential source M under control of the rheostat 45. It is to be understood that this field coil may also be located Within the cylinder depending upon the size of the various elements of the system, the requirement being that a uniform magnetic field is created around the electrodes for the purpose of propagating the arc from the terminal 3? to terminal 38 of the electrodes at the proper rate of speed which, in the standard system, is twenty per second. An electrodynamic are system having similar principles of operation will be found disclosed in my copending application Serial No. 397,826, filed October '7, 1929. Connected across the terminals of the electrode rails 36 is the output of a receiver 59 which receives the incoming signals from an antenna 5 I.

In Fig. 6 an arrangement of a transmitter pickup suitable for both of the above described systems is shown. The light through the cylinders 32 or 6 is projected on an object 53 from which the reflected light is picked up by a photoelectric cell 55 which feeds transmitting equipment 55. The output of transmitter 55 may be broadcast over an antenna 56. It is to be understood that several photoelectric cells may be arranged around the object 53 and connected to the transmitter 55, or that the object 53 may be transparent and in the form of a film in which case the photoelectric cells are placed within the film to receive the emergent light therethrough.

The operation of the scanning system of Figs. 5 and 6 is that an are created at the starting gap 37 is propagated along the rails to the gap 33 by the field of coil 43, the speed being controlled by varying the potential on the rails which determines the current in the arc, and by varying the current in the coil which determines the strength of the field. The are will make one passage along the electrode rails 35 in one twentieth of a second when the system is operating at the standard rate of transmission. As the arc progresses along the rails the light therefrom is projected across an object or screen 53 in the same manner as in Figs. 1 and 2. That is, each lens is separated by six degrees in the case of sixty lenses, the lenses being preferably cylindrical and of a length comparable to the height of a single line of the picture. It is to be understood, of course, that when the output of the receiver 50, which may be receiving television signals transmitted from a similar transmitting system, or any type of system having a corresponding method of scanning, is connected to the electrode rails, the arc will be modulated and the light projection therefrom will vary in accordance with this modulation. Furthermore, it is not necessary to employ a screen for observing the image inasmuch as the picture may be observed directly by looking at the cylinder 3?, the light impinging on the eye in accordance with the modulations of the arc, although it is preferably to use a screen to avoid parallax which will occur at close range.

The above modifications are adaptable to changes by those skilled in the art without departing from the spirit of the invention and the scope of the contribution to the television art disclosed above is defined by the appended claims.

What is claimed is:

1. In a television system, the combination of a moving light source, said source being formed as an electrical discharge between a plurality of electrode rails, means for propagating said discharge along said rails, the movement of said discharge forming one scanning coordinate, ro-

tatable means surrounding said source for concentrating the light from said source into a unit area beam, said rotatable means rotating about an axis coincident with the path of said light source, means for reflecting said light for observation, and means for varying the intensity of said light source in accordance with incoming signals.

2. In a television system, the combination of a moving source of illumination, said source being formed as an electrical discharge between a plurality of electrode rails, means for propagating said discharge along said rails, the movement of said discharge forming one scanning coordinate, rotatable means surrounding said source adapted to gather and concentrate light from said illuminating means into a scanning beam of unit area size, said rotatable means rotating about an axis coincident with the path of said light source, a reflecting medium for said light, a receiver of electrical currents, said currents varying in accordance with the light and shade densities of an object, and means for impressing the output of said receiver on said source of illumination for varying the intensity thereof in accordance with said currents.

3. In a picture transmission system, the combination of a moving source of illumination, said source being formed as an electrical discharge between a plurality of electrode rails, means for propagating said discharge along said rails, the movement of said discharge forming one scanning coordinate, rotatable means surrounding said source adapted to gather and concentrate light from said illuminating means into a unit area beam, said rotatable means rotating about an axis coincident with the path of said light source, and means for directing said light over an object to be scanned in unit sections.

4. In a picture transmission system, the combination of a moving source of light waves, said source being formed as an electrical discharge between a plurality of electrode rails, means for propagating said discharge along said rails, the movement of said discharge forming one scanning coordinate, a rotatable lens system having its axis coinciding with the path of said light source, said lenses gathering and concentrating the light from said source into a concentrated beam of unit area size, and a reflecting system in the path of said beam.

5. In a television system, the combination of an electrodynamic light source, said source being formed as an electrical discharge between a plurality of electrode rails, means for propagating said discharge along said rails, the movement of said discharge forming one scanning coordinate, a rotatable lens system adjacent said light source for gathering light from said source into a unit area beam, said lens system being spirally arranged around the axis formed by said electrodes, and means for transforming the various densities of said light beam into electric current.

6. In a television system, the combination of a substantially uniform light source forming a moving beam of light, said source being formed as an electrical discharge between a plurality of electrode rails, means for propagating said discharge along said rails, the movement of said discharge forming one scanning coordinate, a cylindrical rotatable element in the path of said beam and having thereon lenses for projecting said beam across an object to be scanned, said element rotating about an axis formed by a path of said discharge, and a driving means for said rotatable member to drive said member at the proper relation to bring all of said lenses into the path of said beam during the movement thereof through a definite angle, said rotatable member forming the other scanning coordinate.

7. A television system in accordance with claim 4 in which said driving means includes a motor geared to said rotatable member.

8. In a television system, the combination of a cylindrical member, a plurality of lenses located along the length of said cylinder in spiral formation, a pair of electrode rails located within said cylinder and parallel to the axis thereof, means for producing an electric discharge across said electrodes, means for propagating said discharge along said electrodes, and means for rotating said cylinder at a substantially uniform rate.

9. In a television system, the combination of a pair of electrode rails, means for creating an electrical discharge between said rails, means for propagating said electrical discharge along said rails, the movement of said discharge forming one scanning coordinate, an enclosing member for said'rails, light concentrating means located in said enclosing member and arranged to gather the light from said electrical discharge for pro- ,iection, and means for moving said member to position at least one of said light concentrating means in operative relation to said electrical discharge in succession, said means forming the other scanning coordinate.

10. In a television receiving system, the combination of receiving apparatus for detecting incoming signals, electrode rails, an electrodynamic are adapted to move in a straight line along said electrode rails, means for causing said are to be propagated along said rails, means surrounding said electrode rails and concentric therewith for causing the light from said discharge to illuminate a definite area, and means for connecting the output of said receiving apparatus to said electrode rails for varying the light from said discharge in accordance with the received signals.

11. In a television system, the combination of a pair of electrode rails, means for creating an electrical discharge between said rails, means for creating an electrical field around said rails for moving said discharge therealong, the movement of said discharge forming one scanning coordinate, a member surrounding said rails, the axis of said member being coincident with said electrode rails, a plurality of concentrating lenses located in said member, and means for rotating said member at a definite speed, said speed being in synchronism with the propagation of said discharge along said rails and iorming the other scanning coordinate.

ALEXANDER MCLEAN NICOLSON. 

